Bacteroides thetaiotaomicron has potent anti-inflammatory effects in vitro and in vivo (Kelly et al. Commensal anaerobic gut bacteria attenuate inflammation by regulating nuclear-cytoplasmic shuttling of PPAR-gamma and RelA. Nat Immunol. 2004 January; 5(1):104-12). It modulates molecular signalling pathways of NF-κB (Kelly et al, Commensal anaerobic gut bacteria attenuate inflammation by regulating nuclear-cytoplasmic shuttling of PPAR-gamma and RelA. Nat Immunol. 2004 January; 5(1):104-12). In particular, it stops binding of the active component (RelA) of NF-κB to key genes in the nucleus, thereby preventing the activation of pro-inflammatory pathways (Kelly et al, Supra 2004). The full genome of B. thetaiotaomicron was sequenced and annotated by the Gordon Group (Washington University School of Medicine, USA) in 2003 [Xu et al, A genomic view of the human-Bacteroides thetaiotaomicron symbiosis. Science. 2003 Mar. 28; 299(5615):2074-6].